SBC rocker stud pins / screw-in studs???

http://www.summitracing.com/parts/SUM-1106/

.488/.488 lift

I'm gonna stick this cam in a brand new 10067353 GM crate 350. I've got those "z-28" springs (yet to install - getting close). Should I install some "pins" (mr. gasket sells a kit w/ a drill bit and pins) in the rocker studs? Or should I do screw-in studs? Can I do this mod at home? Tap or drill cast iron by hand? Do I even need to do this? As long as I'm on this subject, could I run the stock, stamped steel, "chevrolet" scripted valve covers, or will the rocker arms hit the valve covers? Thanks for the help.

 

I would not pin the studs - it introduces a stress riser in the stud and with a .488 lift cam you will run the risk of breaking a stud which will mean further work to extract the broken stud(s). If it were mine I would remove the heads and have them machined to insure that all the screw-in studs will be in the same plane and thus all valves will see the same geometry.

 

I think I will pull the heads....Look for them in the cl***ifieds!

 

To install most studs it is not simply tapping the holes and screwing them in, the boss has to be machined down to compensate, so like it was stated above, you will need to take them off and have them done at a machine shop.

Pioneer does sell some screw in studs without the hex part on them (pn 850001), those do not need the bosses machined, but if you take the heads off anyway, i'd just have them done to accept the typical screw in studs.

 

You are overthinking this non problem. Z/28 style springs on a .488 lift cam will not pull studs. If properly installed. Not enuff spring pressure or lift...But, then I've seen pulled studs on stock cam/heads. All it takes is an installer with no clue.

Screw in studs should be done in a machine. Even a drill press will work. Otherwise you get a Porkupine effect and strange wear on valve train parts.

If you use hex base studs. Boss should be shortened .250" in most cases. Add guide plates and you cut .370" or so. Pioneer repair/replacement screw in studs are great for non guide plate stock type heads.

 

I pulled a stud on a 350 Double Humped head. The motor had a 460 lift cam in it.

Pull them and let a shop do it.

 

Crane used to sell a couple of tools to do the job yourself. The first was a tool that cut the boss using the original stud as a guide. Then they had a tool to tap the hole using the stud next to the one you were working on as an index. I think I've still the tools around here somewhere. I used them on lots of heads and never had any problems, but it's been 20 years since I did a "shadetree" job with them.

 

ive built sbc going on 40yrs and ive used over 500 lift cams on stock studs runnin 1.5/1.6 rocker set ups and ive pulled very few studs. and when i did once it was at idle but most times i was reaching way over rpm limits.ive done this many times but with older heads.but nowdays when we get older heads to run we have to fiqure in the age and abuse these heads have had over the yrs.so when we get ready to build i take them to the machine shop and have screw in studs put in.with the cost factor of parts and labor today thats the best insurance you can get. stay away from that mr.gasket **** ansd have a good machine shop set you up,cheaper and safer in the long run.

 

Too big of a cam for the compression read down low on the description, "Fair-lopey idle, mid-upper rpm power. Requires 9.5:1 and higher compression, 2,800+ stall, and gearing.

 

Take into account that pioneer, mr.gasket, and most moroso parts are chinese **** now days. You are better off stock than this ****. If you use a good machine shop they are probabily going to use arp. Be prepared to pay.

 

How do you know that you've 'pulled a stud'. I am sure you can see it but what indication do you get from the engine that the stud is coming out? A bad miss, loud tapping, etc..?

 

Stud pinning has been around and has worked for years. Stud pulling was/is very common on many performance engines including factory builds like those found in Chevys (like Camaro) and Pontiacs (like GTO). Weakness due to pinning never was an issue but screw-in studs (IMO) are easier to install and will withstand those .600"+ lift cams better than pinned.

 

There are factory specs for total accuracy. But if you have a lifter clattering away that you can't adjust, chances are you might have a stud pulling out. Another way to tell is to put a straight edge across the heads of your studs, they should all be the same height.

By the way, pulling a stud is somewhat a figure of speech. I have never seen a stud completely pull out of a head. A stud pulling simply means that it has worked its way out enough to be out of height spec.

 

Crane ****, not Mr. Gasket. There was a difference even back then.

I'll agree that a machine shop is the way to go, but years ago (I guess the last time I used the cutter was in the 70's, so that's closer to 40 years ago than 20) it was kinda hard to find a machine shop that did performance work in "small town Texas".

As far as how to tell if a stud is coming out, when it pulls out it usually pulls out far enough to make the engine miss but sometimes you just get a tick like a lifter out of adjustment. You can check the studs with a straight edge if you have the head stripped. They are all pressed in the same from the factory.

 

Aman on that!!! When machining for screw-in studs and guide plates, have the machinist machine down the top of the stud bosses the same thickness of the guide plates... If the guide plates check at .300" thick, then that's how much the top of the stud bosses need to be milled...

 

Yep! You could tell if you have a pulled stud by removing the valve covers off you motor and checking the top of the studs with a straight edge... 5 minute job...

 

Frenchy here is absolutely correct. Screw in studs are the way to go.

Ususlly the ones that I use have a shoulder and the top of the stud tower needs to be milled off for them to fit properly. You can get screw in studs that are just a plain stud and the only machining is tappng the holes but if you are going so far as to use screw in studs I recommend the shoulder type.

The tapping is the easy part cast iron is really easy to tap, the only hard part is keeping the tap straight, no hill for a stepper. I have a giude that I use now but I tapped a ton of heads without it. Just be careful.

one thing to remember when tapping cast iron is to use no oil.

Next yes with the .488 lift I would use screw in studs.

 

Interesting!

Why is this ******?

 

Cast does not make chips it turns to powder when you tap or machine it, which in turn turns to paste or more like clay with tapping compound. You end up with poor threads in the best case and stuck or broken taps in the worse.

 

Would a light grease have the same effect as oil?

I was always told to use a grease to capture chips and/or filings to insure a cleaner cut.

 

On cast the proper method or at least the proper method that I learned was air. I have used bees wax in the flutes of a tap to keep stuff out of the water or oil galleries on an ***embled engine. I actually was working in a shop once where the very first thing that anyone ever did was machine cast iron and if they used oil on their tool they walked.

 

Deuces,
Don't you need to take the thickness of the nut on the stud and the taper above it into consideraton when you're cutting the boss. I've had rockers that bind up on the taper before the valve lash was set right (farmed out machine shop work, not shadetree. ).

And if your installing guide plates, don't forget to drill out the pushrod guides in the heads.

 

I forgot to mention that...
My bad!...

 

Anyone have a set of LT-1 or L-82 Vette heads they could post pics of???...
If so, then please post away... Thanks!

 

A little O/T but with the cost of machine work to get a set of old Camel hump heads cleaned up and all of the valve seats replaced and studs, guide plate and such it is cheaper to buy a pair of brand new GM Performance Vortec heads ready to bolt on. The big valve 200CC runner heads are around $700 and will make more power than the older heads. The only drawback is you have to use the Vortec intake manifold that has the correct bolt pattern.

 

These are factory 2.02 heads, pretty sure they came with factory screw in studs. Yea, I know they've been cut for different stem seals. There is roughly .400 difference in boss height between the screw in and press in stud bosses.

I'll agree that you're better off running new hipo heads, unless you just want "vintage" heads for some reason.

 

I lost sleep over this same situation.

I had a gorgeous set of highly ported & polished 462 heads that I just didn't want to let go of. However a valve broke requiring a fair amount of machine work and a little bit of welding. After loosing much sleep over it I gave in and bought a set of World Sportsman heads that flow much better than the 462's ever would. After holding on to those 462's for a few years I finally realized I would never use them and sold them. It was like giving up an old friend.

 

The only way to go is Screw in Studs Back in the Day
when I had my Speed Shop all the Street racers
that I set up had to have Screw in studs because
most of them ran High lift Cams
Just my 3.5 cents

 

Two more things to remember, If you use guide plates, you must use hardened pushrods to prevent wear, you can get aftermarket or get them from Chevrolet.
You can get long slot rocker arms from Chevrolet They are easy to identify, on the valve end will be a triangle on stock ones, there will be a zero on the long slot ones. Probably not necessary with your combination, but cant hurt.

 

Don't forget to install the umbrula Valve Seals its worth the
the money or you can do it yourself with a Kit
and dont forget to Clean the Heads after you do this

just my 3.5 cents